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GALCIT REPORT No. \OS,"]:
ll{E
DANIEL
GUGGENHEIM
AIRSHIP
lNSTITUTE
GUGGENHEIM AERONAUTICS LABORAT-ORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
\ , '
J
l C ' r
'•
REPORT 105,J[:--
' l WIND TUNNEL T~"TS ON A 1/75 SCALE HULL OF THE
GOODYEA.R-ZEPPELIN AIRSHIP AKRON Z. R. S . 4 WITH
VARIOUS RING TAIL SURFACES
GAL CIT Pase 12.
Report No. 105;· Part II.
Conclusion
The results show that it is possible to obtain by a ring
tail surface the same static stability and therefore t he same dynrunic
stabili t-y as wit h the normal tail surfaces, at least for l0\7 angles
of attack. At hig:'.1 angles of attack , the st atic and the dynamic stabili­ties
are lower, but, as some calculations made by Dr. Clark B. :.:flli 'i::an
and later to be published showed, the dynamic stability is sufficient
for ring tail No. 6.
Further, it is possible to obtain an improvement of the pres­sure
distrib ution on t he hull tail by the rillG tail surface and t here­fore
to decrease the drag of the hull. In the case of the z.R.s. 4,
the gain of drag is relatively small, because the model has a good
slenderness r atio and therefore a low pressure drag, and the drag of
hull with ring tail is hi gher than with normal tail surfaces (CD : o.0248
for ring No. 6 in comparison to 0.0212, see Part I}.
On the other hand it may be assu..med that the ~a in due to
improving the pressure distribution \7ould be much higher, if other
airsh ip bodies with less slender tails were used. Indeed the d.rar; and
especially the pressure drag of such a body is higher, but by usin~ t he
rins tail it will probably be possible to decrease the drag so that a
thick airship body b~comes useful for the airship builder. A thick bo dy
would have many advantages as regards the structure. For this reason,
i~ is felt that further ring tail tests should be made.
References.
l} Max M. Munk and Elton w. Miller, The Aerodynamic Characteristics of
Seven Frequently Used Wing Sections at Full Reynolds Number.
N.A.C.A. Report No. 233.

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}
)
GALCIT REPORT No. \OS,"]:
ll{E
DANIEL
GUGGENHEIM
AIRSHIP
lNSTITUTE
GUGGENHEIM AERONAUTICS LABORAT-ORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
\ , '
J
l C ' r
'•
REPORT 105,J[:--
' l WIND TUNNEL T~"TS ON A 1/75 SCALE HULL OF THE
GOODYEA.R-ZEPPELIN AIRSHIP AKRON Z. R. S . 4 WITH
VARIOUS RING TAIL SURFACES
GAL CIT Pase 12.
Report No. 105;· Part II.
Conclusion
The results show that it is possible to obtain by a ring
tail surface the same static stability and therefore t he same dynrunic
stabili t-y as wit h the normal tail surfaces, at least for l0\7 angles
of attack. At hig:'.1 angles of attack , the st atic and the dynamic stabili­ties
are lower, but, as some calculations made by Dr. Clark B. :.:flli 'i::an
and later to be published showed, the dynamic stability is sufficient
for ring tail No. 6.
Further, it is possible to obtain an improvement of the pres­sure
distrib ution on t he hull tail by the rillG tail surface and t here­fore
to decrease the drag of the hull. In the case of the z.R.s. 4,
the gain of drag is relatively small, because the model has a good
slenderness r atio and therefore a low pressure drag, and the drag of
hull with ring tail is hi gher than with normal tail surfaces (CD : o.0248
for ring No. 6 in comparison to 0.0212, see Part I}.
On the other hand it may be assu..med that the ~a in due to
improving the pressure distribution \7ould be much higher, if other
airsh ip bodies with less slender tails were used. Indeed the d.rar; and
especially the pressure drag of such a body is higher, but by usin~ t he
rins tail it will probably be possible to decrease the drag so that a
thick airship body b~comes useful for the airship builder. A thick bo dy
would have many advantages as regards the structure. For this reason,
i~ is felt that further ring tail tests should be made.
References.
l} Max M. Munk and Elton w. Miller, The Aerodynamic Characteristics of
Seven Frequently Used Wing Sections at Full Reynolds Number.
N.A.C.A. Report No. 233.